Single photon emission computerized tomography is an increasingly available diagnostic method that uses ionizing radiation for functional, as well as structural, information in patients with suspected disease. We propose to conduct a conference that presents, in a continuing medical education format, the concise and authoritative information needed by practicing nuclear medicine physicians who must evaluate the efficacy of this new technique. In light of competing demand for medical care resources, and the need for rational cost-effective diagnostic strategies, the presentation will emphasize comparison with alternate diagnostic modalities. The symposium will be part of a continuing medical education conference sponsored by the American College of Nuclear Physicians, a non-profit educational and scientific organization. The speaker presentations will be formalized into clinical book chapters suitable for inclusion in a comprehensive monograph dealing with the present status of emission computerized tomography.